1. Field of the Invention
This disclosure generally relates to methods of production of carbonaceous materials. More specifically, this disclosure relates to methods of producing carbon particles for use as anode materials in electrochemical storage cells.
2. Background of the Invention
The requirements for battery performance are largely dependent on their intended application. For example, batteries for use in hybrid electric vehicles may require a very long life cycle, low cost, high gravimetric densities and high volumetric densities, while batteries for portable devices such as cellular phones and camcorders may have the additional requirement of being lightweight. Materials used for the construction of such batteries play a significant role in the batteries' ability to meet the aforementioned requirements.
Carbonaceous materials such as graphite powders have to meet several requirements in order to be used as the anode material in Lithium (Li) ion batteries. The most important requirements are high coulombic efficiency on the first cycle and reversible capacity during the charge/discharge cycles. Many processes have been developed for the production of graphite powders having the aforementioned characteristics. For example, some of the processes use special types of carbon precursors and/or particle forms such as mesophase petroleum, coal tar pitches and beads or fibers. These processes using special types of carbon precursors and/or particle forms are often complicated not only with respect to making the desired precursors but also with regards to controlling the morphology and size. Other processes for the production of said graphite powders involve modification of the regular surfaces of carbon particles by coating the particle with amorphous carbon and other materials designed to increase the coulombic efficiency on the first cycle. For example, surface modification by coating the particles may involve methods such as chemical vapor deposition and pitch coating. These processes, whether using special precursors or carrying out surface modification, add a significant cost to the manufacturing of graphite powders with the desired properties.
Thus, there exists a need for an inexpensive method of producing carbon particles suitable for use as the anode material in batteries.